Savitsky Power Prediction

Discussion in 'Software' started by guest12020101217, Sep 23, 2003.

  1. guest12020101217
    Joined: May 2003
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    guest12020101217 Junior Member

    Thank you for posting your spreadsheet. Hope to have mine finished after new year and will post it here. It's been on back burn abit.
     
  2. Dingo
    Joined: Dec 2003
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    Dingo Junior Member

    Glad I could help. If anyone out there finds an error, let me know please.
    Regarding the use of the spreadsheet, fill the boxes that are coloured yellow with your input; this includes the LCG's (LSP in the program), and velocities, as well as the various parameters regarding the vessel. Click on the 'Voortgaan' putton (proceed), and sit back and wait. The values of resistance and thrust will be calculated. Further on down are calculations for rollstability etc. using various theories from Lewandowski etc.
    I am currently updating this spreadsheet to include planing catamarans based on the theory of Lee (republished by Insel) who builds upon the theory formulated by Savitsky and which takes into account the distance between hulls. If anyone out there has empirical formulas for cats that are as 'easy' to use as Savitsky (without going into triple integral formulas etc.!!) please let me know, otherwise I shall proceed with this one.
     
  3. Guest

    Guest Guest

    Hi Dingo much apreciated your spreadsheet, congratulation for the excellent work.
     
  4. Humberto Rodrìg
    Joined: Dec 2003
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    Humberto Rodrìg Junior Member

    Savitsky`s program


    Here is one: HumbertoR92@hotmail.com
    I will appreciate your help
     
  5. Brent

    Brent Guest

    Password to Unlock the remainder of spreadsheet for translation(Prestasie.xls)

    Dear Sir;

    I was wondering if you were willing to divulge the Password for your resistance spreadsheet posted on boatdesign.net(Prestasie.xls). I want to unlock the remainder of spreadsheet for translation and use if for my senior design project at school(working on a high speed sportfish concept).

    Thanks,

    Brent

    Email: wyy551@yahoo.com


     
  6. Dingo
    Joined: Dec 2003
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    Dingo Junior Member

    Brent, I have written another spreadsheet for Savitsky/Hadler/Blount etc. (in English) that is cleaned up and easier to use. I will sent that to you if you desire. The calculations are hidden but I can give you the details to unlock it if you need to translate any Dutch/Afrikaans that I made notes or references in (old habit I picked up studying in South Africa).

     
  7. Humberto Rodrìg
    Joined: Dec 2003
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    Location: Venezuela

    Humberto Rodrìg Junior Member

  8. stillgar
    Joined: May 2004
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    stillgar New Member

    Dingo:

    Could you please email me a copy of your translated spreadsheet?

    stillgar_@hotmail.com

    Regards,
     
  9. albresco
    Joined: May 2004
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    albresco New Member

    Please send me a copy of your English spread sheet as well.
    Thank you
    albresco@shaw.ca
     
  10. cgorton
    Joined: Aug 2003
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    cgorton Junior Member

    I'd love a copy of your English translation spreadsheet- thanks!

    Craig

    cg@zurnyachts.com
     
  11. Dingo
    Joined: Dec 2003
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    Location: South Australia

    Dingo Junior Member

    Spreadsheet

    Here is my spreadsheet. I've made it easier to use, translated it into English with a help file and hidden the calculations (password is Dingo to view it on a separate sheet). I've still yet to add catamaran resistance results, but will do so as soon as I have time. Any problems or errors, let me know please. By the way, be careful when predicting drag around the hump speed; there are other methods that can be used, but this is good for estimating.

    Dingo
     

    Attached Files:

  12. albresco
    Joined: May 2004
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    albresco New Member

    Thank you for the sreadsheet post. Looks great!!
     
  13. Dingo
    Joined: Dec 2003
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    Location: South Australia

    Dingo Junior Member

    This reply is for Nev, but I will republish it here in case others have the same questions:
    If you go to the Help tab in the spreadsheet, most of the definitions that you wrote in red are explained with diagrams. Regarding the sheet 'Berekenings' (Dutch for Calculations): the sheet is hidden but can be turned on and inspected (password is Dingo). All the background calculations are there. You ask why the thrust is more than the drag: it is because the drag is in the direction of motion (ie. horizontal), but the thrust acts at an angle slightly downward, so it has to be slightly higher in order to get the equal amount of horizontal force to counteract the drag. Regarding the Go button: press the button once you change a value. The trim will change to almost zero on the first run, then increment upwards until it reaches the equilbrium value for zero moment. If #VALUE appears, it means that the resistance can't be predicted for those particular given parameters.
     
  14. ars-technica
    Joined: Apr 2004
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    Location: Italy

    ars-technica Naval Architect

    Make 2 column
    clo clb
    0.1 value obtained with =clo-....
    0.2 value obtained with =clo-....
    make this for all number of clo you need
    then use the function search to discover the value you need in that moment.
    warning taht search function give you the value incorect if you do not impost an interpolation before...



     

  15. Danielsan
    Joined: Jul 2004
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    Location: Belgium (Europe)

    Danielsan Amateur designer-builder?

    Is this OK?

    Hi,
    I did use the last version (English) of Dingos spreadsheet

    Any one thinks this can be a correct result? I should need 160HP to get my boat planning at 50kts

    http://www.boatdesign.net/forums/showthread.php?t=4610 (my boat)

    THX in advance,

    Daniel Peeters

    Inputs

    Hull Beam B 9.18 feet
    VCG VCG 1.02 feet = 0.311 metres
    Displacement D 6,800 lbf = 3,084 kg
    Deadrise @ Transom b T 27 °
    Deadrise @ Amidships b )0( 27 °
    Distance to Amidships L )0( 12.160 feet = 3.706 metres
    f 1.00 feet = 0.305 metres
    e 15.00 °
    q 0.000 °

    Minimum Speed Vmin 6.1 kn = 10.3 feet/s This is the minimum speed valid for this analysis
    Maximum Speed Vmax 132.4 kn = 223.4 feet/s This is the maximum speed valid for this analysis

    Number Number of Propellers N 1

    Trim Tab Chord cF 1 feet = 0.305 metres
    Span Ratio s 0.333 ( <= 1 )
    Deflection Angle d 0 °

    Rudder Chord crudder 0.00 feet = 0.000 metres
    Thickness t 0.00 feet = 0.000 metres
    Area Arudder 3.60 feet2 = 0.334 m2
    Centrepoint xc -0.80 feet from transom = -0.243 metres (+ve fwd)
    yc -0.60 feet from baseline = -0.183 metres (+ve up)

    Shaft Diameter of Shaft Fshaft 0.00 feet = 0.000 metres
    Length of Shaft & Hub l 0.00 feet = 0.000 metres
    Centrepoint xc 5.50 feet from transom = 1.676 metres (+ve fwd)
    yc 0.00 feet from baseline = 0.000 metres (+ve up)

    Strut Chord cstrut 0.00 feet = 0.000 metres
    Thickness t 8.00 feet = 2.438 metres
    Area Astrut 0.75 feet2 = 0.070 m2 ****
    Centrepoint xc 3.50 feet from transom = 1.067 metres (+ve fwd)
    yc 2.00 feet from baseline = 0.610 metres (+ve up)

    Output V LCG t D T Peffective h
    [kn] [ft] [metres] [°] [lbf] [kN] [lbf] [kN] [ehp] [ekW] [ft] [metres]
    6 10.5 3.2 10.3662 595 2.6 659 2.9 11 8 3.51 1.070
    7.5 10.5 3.2 11.5474 1,087 4.8 1,215 5.4 25 19 3.51 1.070
    10 10.5 3.2 14.2537 1,665 7.4 1,909 8.5 51 38 3.29 1.003
    12.5 10.5 3.2 > 15° #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
    13 10.5 3.2 > 15° #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
    14 10.5 3.2 > 15° #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
    15 10.5 3.2 > 15° #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
    17.5 10.5 3.2 > 15° #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
    20 10.5 3.2 14.0987 1,583 7.0 1,812 8.1 97 73 1.38 0.421
    25 10.5 3.2 11.0293 1,318 5.9 1,467 6.5 101 75 1.18 0.360
    30 10.5 3.2 8.7581 1,151 5.1 1,257 5.6 106 79 1.09 0.332
    35 10.5 3.2 7.1278 1,065 4.7 1,149 5.1 114 85 1.04 0.317
    40 10.5 3.2 5.9385 1,045 4.6 1,118 5.0 128 96 1.01 0.308
    45 10.5 3.2 5.0493 1,081 4.8 1,151 5.1 149 111 0.99 0.302
    50 10.5 3.2 4.368 1,169 5.2 1,239 5.5 179 134 0.97 0.296
     
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